"Isn't it awfully good to have a penis," Eric Idle mused in the greatest 35-second song ever written and I believe he's telling the truth: having a stiffy is probably spiffy. Erections are such hopeful things, like carrying a little optimist around in your pocket, one imagines.

The penis provides lots of pleasure and keeps the human race going in its capacity as a reproductive organ. There's all kinds of interesting facts and facets to the human penis and there are some in the animal world that could easily have been designed by Dali. Now's your chance to get to know them a little better.

1. Spiny Norman no more.

Evolution has discarded many parts of the human penis, including ... its spines?

Penile spines are little tiny ridges made of a hard tissue called keratin, and line the outside of the penis. They look (I think) a bit like those punk-inspired accessories that are so popular these days. Lots of animals, including the chimpanzees, still have penis spikes. Christine Dell-Amore of National Geographic News writes that the human genome project gave us the information that the ancestor we share with the chimps also had the spines.

But that was so six million years ago. The code for the "penile spine enhancer" was deleted from the human androgen receptor gene, says Nature (androgens are male sex hormones) and Dell-Amore reports that it happened "before our common ancestor split into modern humans and Neanderthals about 700,000 years ago." Quite a few deletions were discovered — 510, if you please — and gave us other spiffy changes like having bigger brains and not having whiskers.

2. How the human lost his bone, er, baculum.

Another thing the human penis lost along the way — gosh, is it forgetful or what? — was its baculum, or penis bone. Some animals have what's called an os penis, one containing a bone which keeps them rigid long enough to deliver sperm into the female's reproductive tract. Most primates have one, but human males rely solely on blood pressure or hemodynamics for rigidity. Lauren Reid of Science Alert writes that the baculum is usually stored in the animal's abdomen until needed, when abdominal muscles push it out. One of its good qualities is speed: it's more reliable than waiting for blood flow to work and allows for quick copulation.

In The Selfish Gene, evolutionary biologist Richard Dawkins describes the os penis as clearly being an easier way to maintain an erection. He theorizes that the reason we lost such a helpful trait is that hemodynamics allow females to better gauge male sexual health when choosing a partner. From diabetes to depression, there are numerous health factors that can cause erectile trouble and "females could glean all kinds of clues about a male's health and the robustness of his ability to cope with stress, from the tone and bearing of his penis," clues a bone would obfuscate because "anybody can grow a bone in the penis; you don't have to be particularly healthy or tough."

Another charming tidbit from Reid: "There is also a female version of the baculum in some species which has a rather lovely name — the "baubellum," or "os clitoris."

3. The adventurous penises of the argonauts.

So the human penis is strong, but not strong enough to run away and mate on its own, leaving the rest of the guy to relax and watch TV.

One animal that does have that ability is the argonaut octopus. Stefan Anitei writes on Softpedia that in octopi, the third right arm of the male is the penis, which is detachable and is called the hectocotylus. The hectocotylus deposits sperm packets called spermatophores into the gills' cavity of the female and will regenerate a new third arm next season.

Some human males will be jealous of the fact that the male argonaut doesn't ever have to bother with any intimacy hooey. Some other octopi will at least get close — they recognize their partners by smell and touch. But the argonaut's hectocotylus wanders off on its own when the spermatophores are formed and goes into the "mantle cavity to fecundate the eggs."

Wow, just imagine how much more the argonaut can get done in a day! He can go to the bank, the post office and the liquor store all while helping perpetuate the speceis.

4. While you were sleeping.

The human penis may not be that much of a multitasker, but it does get some exercise while the rest of the body is busy with something else: sleeping.

One of the 8 Things You Didn't Know About Your Penis pointed out by Martin Downs on WebMD is that to keep it healthy you've got to use it, i.e., get erections. But if something is going on in your waking life that's preventing that from happening, your penis has your back: it works out while you snooze. Doesn't matter what they're dreaming about; most men have 3-5 erections a night.

To add insult to difficulty, "Without regular erections, penile tissue can become less elastic and shrink, making the penis 1-2 centimeters shorter," Downs writes.

Jeez, way to kick a guy when he's down. It's just like when the bank charges you a fee…because you don't have enough money in your account. Either way you're unfairly shortchanged.

5. What a drag.

If you want to help your penis help you, there's something you might want to do: quit smoking.

Web M.D. Jeanie Lerche Davis reports that a study of Chinese men found, among other things, that "Men who currently — and formerly — smoked were about 30% more likely to suffer from impotence." Smoking and erectile dysfunction are both connected (individually) with plaque that builds up in the arteries: it restricts blood flow and potentially causes ED, among other problems. The habit could also be making your erections smaller.

Men's Health reports in 8 Strategies for Stronger Erections that "In addition to damaging blood vessels, smoking may cause damage to penile tissue itself, making it less elastic and preventing it from stretching," says urologist Irwin Goldstein.

So where there's smoke…there may not as much fire as you'd like.

6. Those amazing animals.

The variation nature has gone to the trouble of putting into the penises of the world is dizzying. And sometimes dwarfing.

Elephants are big (you learn something new every time we talk, don't you?) and their penises are proportionately enormous to the point where if you click the link to this piece by science writer Ed Yong, you'll see how you could almost mistake this elephant's schlong for a skinny leg. Yong says the elephant also swatted flies and scratched his belly with it. Elephant penises are referred to as "prehensile," although it doesn't say in the piece that he picked up anything with it...except, we suspect, a lucky lady elephant.

Here on National Geographic, Yong also shares the weirdness that is the alligator penis. This member is eternally erect, "ghostly white," doesn't inflate at all, which makes it highly unusual, is filled with layer upon layer of collagen (even where blood would normally flow) and, as Yong notes, must have scared the bejesus out of this researcher when one appeared to rise from this dead reptile.

Then there's the cute little echidna, a prehistoric, egg-laying hedgehog-like mammal whose penis has four heads. Click on the second picture and see how happy he looks (even though his name is Grumpy).

Lucy Cooke writes in National Geographic that, "The reason why the echidna's penis has four heads is still up for grabs. The female echidna has two love canals and Stewart [Nicol, echidna researcher] believes that the penis works like a double double-barreled shotgun, firing out of the two heads on one side, and then again quite quickly on the other. Given the fact Mr. Echidna has no idea which side his lady's egg will be released this might increase his chances of fertilization."

And may be one reason why a species who walked with dinosaurs is still here to charm us with his ornate love machine.

7. Getting a big head.

So the elephant's penis is big, but the human male's is huge among primates. Correcting for overall body size, it's twice as big as the chimp's, which may be why they're always screaming.

At any rate, the strong, straight shaft, large glans or head and coronal ridge look the way they do for a reason, and the reason is probably semen delivery and displacement — delivery of one's own and displacement of another male's.

First let's talk about length. Bering tells us that evolutionary psychologist Gordon Gallup and coauthor Rebecca Burch wrote a 2004 paper conjecturing that the lengths the penis can reach and the force of human ejaculate can delivery sperm into the uppermost part of the vagina and that a longer penis would be advantageous not only for reaching the vagina's deeper recesses but to displace sperm that might have been left by another male. Interesting, especially since magnetic imaging of couples having sex is what tells us how the far the penis can go and how it expands inside the vagina.

But it gets way, way better.

The distinct arrow-like shape of the penis would be good for displacement, Gallup figured, because of the "upsuck," (not kidding) caused by thrusting. If there was anyone else's sperm in there, that ridge would effectively scoop it all out. To test this, Gallup and his researchers got some "prosthetic genitals from erotic novelty stores," including a faux vagina and three faux penises, one with a coronal ridge extending .2 inches from the shaft, one extending out .12 inches and one with no glans at all, which was the control. They made a simulated semen solution of flour and water, put it inside the "vagina," and the three dummy weiners were then inserted to see how much ersatz sperm they could displace.

Imagine going to the office that day. To anyone who thinks science is monotonous, I have two words: puh leeze.

Anyway, Gallup was right. The smoothie removed only 35.3 percent while the two with the wider coronal ridges removed 91 percent and the deeper they were inserted the more effective scoopers they were.

8. Gimmie some skin.

Everyone knows the human penis can be very giving, but who knew that generosity extended to the medical community? Foreskin, the retractable piece of skin that covers the penis (it's also called the prepuce, a word that also refers to the skin covering the clitoris) has been used in a lab to grow artificial skin cells for burn victims. And if you've ever been impressed with a "grower" check out prepuce power:

"A piece of foreskin the size of a postage stamp can produce approximately 4 acres of skin tissue in the laboratory [source: Strange]," writes Molly Edmonds of How Stuff Works. The foreskins of circumcised infants are thought to work well in this way — better than donor skin — because the infant cells are not rejected by the adult body's immune system. "If they did," Edmonds writes, "mothers' bodies would reject fetuses [source: Skloot]." Discovery Channel says that lab-grown skin is less likely to be rejected by a patient and also less likely to cause infection.

Foreskin tissue donated with parental consent to Germany's "Skin Factory" at the Fraunhofer Institute in Stuttgart is used to grow artificial skin used for consumer product testing that "could someday replace animal testing," writes Eric Pfieffer of Yahoo News. Pfieffer quotes the German Herald as reporting that the cells are grown "on a layer of collagen and connective tissue." Eventually they are injected "into a gel that causes them to grow into a sheet that simulates the epidermis. The layers are then fused together, creating a replica of natural human skin."

Circumcision is definitely a controversial issue, but it's kind of hard not to be for skin.

9. Something fishy.

To wrap things up, it's fair to say that doing this story has certainly caused male genitals to be on my mind...but there's one species of fish that wears his on his head.

The 2cm-long Phallostethus cuulong was discovered in Vietnam in 2009 by Koichi Shibukawa, a researcher from the Nagao Natural Environment Foundation in Tokyo, writes New Scientist's Michael Marshall. The little fella doesn't actually have a penis as we understand them, but has a "priapium, which faces backwards and looks like a muscular nozzle. It's actually a modification of the fish's pectoral and pelvic fins" and the reproductive organs hang from his chin, a characteristic of all priapiumfish, named for Priapus, Greek god of many things including male reproductive power.

The priapiumfish may also be singular in this world of digital sharing in that no one has ever seen them mating. It's thought, however, that the male keeps the female in place with two appendages, one that looks like a saw (the ctenactinium), the other like a rod, (toxactinium) which he holds on either side of her head while transferring sperm.